This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Iron is the most abundant transition element on Earth, and is vital for a wide range of biological processes in all known organisms. Paradoxically, iron is largely insoluble under the oxidizing conditions present in the aqueous milieu of living cells, and high levels of dissolved iron are usually toxic. Many organisms address this difficulty using a class of proteins called ferritins. Ferritins form a symmetric cage out of 12 identical subunits;iron sequestered by ferritin forms an iron oxide nanoparticle inside this protein cage. Our laboratory is interested in using ferritin (and similar protein cages) to grow inorganic nanoparticles with controlled compositions and novel material properties. To this end, we want to investigate how iron ions enter (and leave) the ferritin cage. We intend to use the TeraGrid facility for all-atom molecular dynamics studies of ferritin in an aqueous solution, in an effort to understand the structural and dynamical features of the system that control the rate at which ions can enter and leave the cage. Specifically, we suspect that amino acid substitutions at several specific sites will influence the opening of pores in the protein shell. By understanding the effects of these mutations at a molecular level, we can better design engineered protein cages for use as nanoscale reaction containers.